Low-profile cable armor

ABSTRACT

Disclosed is a cable assembly including at least one conductor and a metal sheath disposed over the at least one conductor, the metal sheath including a continuous strip of metal having a plurality of revolutions. A first revolution of the plurality of revolutions may include a first section having a curved profile extending into an interior cavity of the metal sheath, and a second section extending from the first section, the second section extending along a lengthwise axis, wherein a length of the second section, along the lengthwise axis, is at least two times as large as a diameter of the first section when the metal sheath is in a linear configuration. The first revolution may further include a third section extending from the second section, the third section including a free end terminating within a recess defined by a curved profile of a first section of an adjacent revolution.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation-in-part application of co-pending non-provisionalapplication Ser. No. 17/408,629, filed on Aug. 23, 2021 and titled“LOW-PROFILE CABLE ARMOR”, which is a continuation application of U.S.Pat. No. 11,101,056, filed on Sep. 23, 2019 and titled “LOW-PROFILECABLE ARMOR”, the entirety of which applications are incorporated byreference herein.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to armored cables. Moreparticularly, the present disclosure relates to a low-profile armoredcable assembly.

DISCUSSION OF RELATED ART

Armored cable (“AC”) and Metal-Clad (“MC”) cable provide electricalwiring in various types of construction applications. The type, use, andcomposition of these cables should satisfy certain standards as setforth, for example, in the National Electric Code® (NEC®). (NationalElectrical Code and NEC are registered trademarks of National FireProtection Association, Inc.) These cables house electrical conductorswithin a metal armor. The metal armor may be flexible to enable thecable to bend, while still protecting the conductors against externaldamage during and after installation. The metal armor which houses theelectrical conductors may be made from steel or aluminum, copper-alloys,bronze-alloys and/or aluminum alloys. Typically, the metal armor isformed from strip steel, for example, which is helically wrapped to forma series of interlocked sections along a longitudinal length of thecable. Alternatively, the metal armor may be made from smooth orcorrugated metal.

While installing MC cable, the product may be passed through wooden ormetal studs. Prior art metal armor profiles often have more pronouncedpeaks, with deeper and wider valleys between adjacent peaks. Thisconstruction often causes the cable to grab and get hung up on edges ofthe studs, requiring readjustment of the cable while installing, whichleads to installer fatigue, slower installation, and potential damage tothe studs.

A need therefore exists for an armored cable that addresses at leastsome of the above issues.

SUMMARY OF THE DISCLOSURE

Exemplary approaches provided herein are directed to an armored cableassembly. In one approach, a cable assembly may include at least oneconductor and a metal sheath disposed over the at least one conductor,the metal sheath including a continuous strip of metal having aplurality of revolutions. At least a first revolution of the pluralityof revolutions may include a first section having a curved profileextending into an interior cavity of the metal sheath, and a secondsection extending from the first section, the second section extendingalong a lengthwise axis, wherein a length of the second section, alongthe lengthwise axis, is at least two times as large as a diameter of thefirst section when the metal sheath is in a linear configuration. Thefirst revolution of the plurality of revolutions may further include athird section extending from the second section, the third sectionincluding a free end terminating within a recess defined by a curvedprofile of a first section of an adjacent revolution of the plurality ofrevolutions.

In another approach, a metal-clad (MC) cable assembly may include aplurality of conductors cabled together, and a metal sheath comprising asingle metal strip wound around the plurality of conductors in a seriesof helical revolutions extending along a lengthwise axis. A firsthelical revolution of the series of helical revolutions may include afirst section having a profile extending into an interior cavity of themetal sheath, a second section extending from the first section, thesecond section extends into an interior cavity defined by the series ofhelical revolutions, and a third section extending from the secondsection. The third section may include a free end terminating within arecess defined by a curved profile of a first section of an adjacenthelical revolution of the series of helical revolutions, wherein thefirst section and the second section of the first helical revolutionconnect at a first inflection point, wherein the second section and thethird section of the first helical revolution connect at a secondinflection point, and wherein a length of the second section of thefirst helical revolution is at least three times as large as a distancebetween the second inflection point of the first helical revolution anda first inflection point of the adjacent helical revolution of theseries of helical revolutions when the metal sheath is in a linearconfiguration.

In yet another approach, a metal-clad (MC) cable assembly may include aplurality of conductors extending along a lengthwise axis and a metalsheath comprising a single, continuous metal strip wound helicallyaround the plurality of conductors in a series of convolutions, theseries of convolutions comprising a first convolution in direct abutmentwith a second convolution. The first convolution may include a firstconvolution first section having a first curved profile, wherein thefirst semicircular profile extends into an interior cavity of the metalsheath, and a first convolution second section extending from the firstconvolution first section at a first convolution first inflection point,the first convolution second section extending along to the lengthwiseaxis. The first convolution may further include a first convolutionthird section extending from the first convolution second section at afirst convolution second inflection point. The second convolution mayfurther include a second convolution first section having a secondcurved profile, wherein the second semicircular profile extends into theinterior cavity of the metal sheath, a second convolution second sectionextending from the second convolution first section at a secondconvolution first inflection point, the second convolution secondsection extending along the lengthwise axis, and a second convolutionthird section extending from the second convolution second section at asecond convolution second inflection point. The first convolution thirdsection may terminate within a recess defined the second convolutionfirst section, wherein a length of the first convolution second section,along the lengthwise axis, is at least two times as large as a diameterof the first convolution first section when the metal sheath is in alinear configuration.

In yet another approach, a method of forming a metal-clad (MC) cableassembly may include cabling a plurality of conductors together, andhelically wrapping a single continuous strip of metal around a pluralityof conductors to create a metal sheath, the metal sheath comprising aseries of helical revolutions extending along a lengthwise axis. Atleast two helical revolutions of the series of helical revolutions mayeach include a first section having a curved profile, wherein the curvedprofile is concave relative to the lengthwise axis, a second sectionextending from the first section, the second section extending parallelto the lengthwise axis, and a third section extending from the secondsection. The third section may include a free end terminating within arecess defined by a first section of an adjacent helical revolution ofthe series of helical revolutions, wherein the first section and thesecond section connect at a first inflection point, wherein the secondsection and the third section connect at a second inflection point, andwherein a length of the second section is at least three times as largeas a distance between the second inflection point and the firstinflection point of the adjacent helical revolution of the series ofhelical revolutions when the metal sheath is in a linear configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate exemplary approaches of thedisclosed armored cable assembly so far devised for the practicalapplication of the principles thereof, and in which:

FIG. 1 is a side view of an armored cable assembly according toembodiments of the present disclosure;

FIG. 2 is a cross-sectional view of the armored cable assembly of FIG. 1according to embodiments of the present disclosure:

FIG. 3 is a side view of the armored cable assembly of FIG. 1 accordingto embodiments of the present disclosure;

FIG. 4A is a cross-sectional view of the armored cable assembly of FIG.3 according to embodiments of the present disclosure:

FIG. 4B is a cross-sectional view of an armored cable assembly accordingto embodiments of the present disclosure;

FIG. 4C is a cross-sectional view of an armored cable assembly accordingto embodiments of the present disclosure;

FIG. 4D is a cross-sectional view of an armored cable assembly accordingto embodiments of the present disclosure;

FIG. 4E is a cross-sectional view of an armored cable assembly accordingto embodiments of the present disclosure;

FIG. 4F is a cross-sectional view of an armored cable assembly accordingto embodiments of the present disclosure;

FIG. 4G is a cross-sectional view of an armored cable assembly accordingto embodiments of the present disclosure;

FIG. 4H is a cross-sectional view of an armored cable assembly accordingto embodiments of the present disclosure;

FIG. 5A is a close-up cross-sectional view of a portion of the armoredcable assembly of FIG. 4 according to embodiments of the presentdisclosure;

FIG. 5B is a close-up cross-sectional view of a portion of an armoredcable according to embodiments of the present disclosure;

FIG. 5C is a close-up cross-sectional view of a portion of an armoredcable according to embodiments of the present disclosure;

FIG. 6 is a side cross-sectional view of an example revolution of ametal sheath according to embodiments of the present disclosure;

FIGS. 7A-7B are side cross-sectional views of an example revolution andmetal sheath according to embodiments of the present disclosure;

FIGS. 8A-8B are side cross-sectional views of an example revolution andmetal sheath according to embodiments of the present disclosure;

FIG. 9 is a side cross-sectional view of an example metal sheathaccording to embodiments of the present disclosure;

FIG. 10 demonstrates an MC cable assembly according to embodiments ofthe present disclosure;

FIG. 11 demonstrates an MC cable assembly in use with a reel accordingto embodiments of the present disclosure;

FIGS. 12A-12B demonstrates an MC cable assembly during installationaccording to embodiments of the present disclosure; and

FIG. 13 is a flowchart of a method for forming an MC cable according toembodiments of the present disclosure.

The drawings are not necessarily to scale. The drawings are merelyrepresentations, not intended to portray specific parameters of thedisclosure. The drawings are intended to depict exemplary embodiments ofthe disclosure, and therefore are not to be considered as limiting inscope. In the drawings, like numbering represents like elements.

Furthermore, certain elements in some of the figures may be omitted, orillustrated not-to-scale, for illustrative clarity. The cross-sectionalviews may be in the form of “slices”, or “near-sighted” cross-sectionalviews, omitting certain background lines otherwise visible in a “true”cross-sectional view, for illustrative clarity. Furthermore, forclarity, some reference numbers may be omitted in certain drawings.

DESCRIPTION OF EMBODIMENTS

The present disclosure will now proceed with reference to theaccompanying drawings, in which various approaches are shown. It will beappreciated, however, that the disclosed armored cable assembly may beembodied in many different forms and should not be construed as limitedto the approaches set forth herein. Rather, these approaches areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the disclosure to those skilled in the art. Inthe drawings, like numbers refer to like elements throughout.

To address the above identified drawbacks of the prior art, embodimentsof the present disclosure provide a novel exterior armor profile that isrelatively flat and creates smaller valleys between adjacentconvolutions. The flat profile allows cables installers to more easilypull the cable through, studs, cable trays, supports, etc., and withless hang ups and friction. Furthermore, the cable of the presentdisclosure doesn't nest into other cables or itself. As a result, lessentanglements occur, for example, when pulling two or more cables alongone another. The flat profile further allows for easier unidirectionalpulling installation. Still furthermore, cables having the armor profileof the present disclosure have a smaller diameter and bend radius forpackaging and installation, while still meeting performance requirementsfor MC cables (e.g., minimum crush-resistance and flexibility).

Referring now to the side view of FIG. 1 and to the side cross-sectionalview of FIG. 2, an exemplary cable assembly 100 according to embodimentsof the present disclosure will be described in greater detail. As shown,the armored cable assembly (hereinafter “assembly”) 100 may include aplurality of conductors 102 extending either parallel to one another orcabled together, e.g., in either a right or left hand lay. Theconductors 102 generally extend along a lengthwise axis ‘LA’ of theassembly 100 and may be enclosed by a metal sheath 105. Althoughnon-limiting, the assembly 100 may be a Metal-Clad (MC) cable assembly.In some embodiments, only a single conductor is present within the metalsheath 105. Although non-limiting, the conductors 102 may include one ormore copper wires covered with a thermoplastic insulation (e.g.,THHN/THWN with a 90° C. rating).

The metal sheath 105 may be formed as a seamless or welded continuoussheath having a generally circular cross section with a thickness ofabout 0.005 to about 0.060 inches. The metal sheath 105 may be formedfrom a flat or shaped metal strip, the edges of which are helicallywrapped and interlock to form a series of revolutions 108A-108N alongthe length of the conductors 102. In this manner, the metal sheath 105allows the resulting assembly 100 to have a desired bend radiussufficient for installation within a building or structure. The metalsheath 105 may also be formed into shapes other than circles such as,but not limited to, rectangles, polygons, ovals and the like. The metalsheath 105 provides a protective metal covering around the conductors102.

The metal sheath 105 may be formed by using an armoring machine tohelically wind one or more metal strips around the conductors 102. Theedges of the metal strip interlock to form a series of peaks 114 andvalleys 116 along the length of the metal sheath 105, as will bedescribed in greater detail below.

As shown, a binder 110 may be wrapped around the conductors 102. Itshould be understood that a greater or fewer number of conductors can beutilized and the assembly 100 can be utilized without a binder,depending on the particular application in which the assembly 100 isbeing used. Furthermore, although not shown, it will be appreciated thatassembly 100 may include one or more filler members within the metalsheath 105. In one approach, a longitudinally oriented filler member isdisposed within the metal sheath 105 adjacent to the plurality ofconductors 102 to push the plurality of conductors 102 radially outwardand into contact with an inside surface of metal sheath 105. The fillermember can be made from any of a variety of fiber or polymer materials.Furthermore, the filler member can be used with MC cable assemblieshaving any number of insulated conductor assemblies.

Turning now to FIGS. 3-4A, the metal sheath 105 according to embodimentsof the present disclosure will be described in greater detail. As shown,the metal sheath 105 may be formed of a continuous metal strip, such asaluminum, having revolutions 108 that overlap or interlock, withuniformly spaced peaks 114 and valleys 116 defining an outer surface 118of the sheath 105. The revolutions 108 extend helically around thelengthwise axis ‘LA’ (FIGS. 1-2). In some embodiments, each of therevolutions 108 may include a first section 120 having a curved,radiused, bowed, arched, or semicircular profile extending into aninterior cavity 128 of the metal sheath 105. In other embodiments, thefirst section 120 may have an alternative profile such as, but notlimited to, oval (FIG. 4B), rounded u-shaped (FIG. 4C), v-shaped (FIG.4D), j-shaped (FIG. 4E), and others. In various embodiments, a radius ofthe first section 120 may be constant or varied. In various embodiments,the first section 120 may include one or more flat sections/surfaces andone or more curved sections/surfaces. Adding one or more flattenedsections may increase movement and create a more flexible sheath 105.Furthermore, in various embodiments, the first section 120 may have aconstant or varied thickness between a first end 121 and a second end123, wherein the thickness is measured between a first surface 127 and asecond surface 129. As best shown in FIG. 4A, the first surface 127generally faces away from the interior cavity 128 while the secondsurface 129 generally faces the interior cavity 128.

As further shown, each revolution 108 may include a second section 122integrally formed with, and extending from, the first section 120. Insome embodiments, the second section 122 has a generally planar or flatouter profile extending along the lengthwise axis. That is, a planedefined by an inner surface 133 and/or an outer surface 135 of thesecond section 122 may be parallel with the lengthwise axis when themetal sheath 105 is in a straight or linear configuration. Furthermore,in various embodiments, the second section 122 may have a constant orvaried thickness between a first end 137 and a second end 139, whereinthe thickness is measured between the inner surface 133 and/or the outersurface 135. Still furthermore, second sections 122 on circumferentiallyopposite sides of the metal sheath 105 (e.g., top and bottom) generallyextend parallel to one another when the metal sheath 105 is in astraight or linear configuration. In some embodiments, a thickness ofthe first section 120 is the same as a thickness of the second section122.

In other embodiments, as shown in FIG. 4F, a plane defined by the innersurface 133 and/or the outer surface 135 of the second section 122 maybe non-parallel with the lengthwise axis when the metal sheath 105 is ina straight or linear configuration. For example, the second section 122may extend at an angle between 0.1°-15° relative to the lengthwise axis.In some embodiments, each of the second sections 122 may extend along asame plane when the metal sheath 105 is in a straight or linearconfiguration. In other embodiments, one or more of the second sections122 may generally extend along a different plane from another of thesecond sections 122 when the metal sheath 105 is in a straight or linearconfiguration.

As shown in FIG. 4G, in some embodiments, the second section 122 mayinclude one or more flat sections/surfaces 148 and one or more curvedsections/surfaces 149. As shown in FIG. 4H, in some embodiments, thesecond section 122 may have an undulating or curvilinear profileincluding, e.g., one or more peaks 151 and one or more valleys 152.

Each of the revolutions 108 may further include a third section 124integrally formed with, and extending from, the second section 122. Asshown, the third section 124 may include a free end 125 angled towardsthe interior cavity 128 of the metal sheath 105. The third section 124mechanically interlocks with the first section 120. In some embodiments,the third section 124 may include one or more flat sections/surfaces andone or more curved sections/surfaces. In various embodiments, the thirdsection 124 may have a constant or varied thickness along its length. Insome embodiments, a thickness of the third section 124 is the same as athickness of the second section 122 and the first section 120.

Turning now to FIGS. 5A-5C, portions of the metal sheath 105 accordingto embodiments of the present disclosure will be described in greaterdetail. As shown, the free end 125 of the third section 124 ofrevolution 108A may extend into and terminate within a recess 130defined by the profile of the first section 120 of adjacent revolution108B. As shown in FIG. 5A, the free end 125 of the third section 124 mayextend towards the interior cavity 128 at a non-zero angle (e.g.,between 1-25°) with respect to a plane 132 extending through the firstsection 120. Orienting the free end 125 at a non-zero angle may provideincreased flexibility for revolution 108A and the adjacent revolution108B. In other embodiments, as shown in FIG. 5B, the free end 125 mayextend towards the interior cavity 128 parallel to the plane 132.Orienting the free end 125 parallel to the plane 132 may provide bettercrush resistance for the sheath 105. In yet other embodiments, as shownin FIG. 5C, the free end 125 of the third section 124 may extend towardsthe interior cavity 128 at a second non-zero angle. That is, to improvecrush resistance of the sheath 105, the free end 125 of the thirdsection 124 may be positioned closer to the first end 121 of the firstsection 120 than to the second end 123 of the first section 120. Asshown, the plane 132 may extend perpendicular to the inner surface 133of the second section 122 and through a trough or bottom most point 134of the first section 120.

The valley 116 can be defined by a valley width ‘VW’, which may bemeasured from a first inflection point 138 located at an intersection ofthe first section 120 and the second section 122 of revolution 108B, anda second inflection point 140 located at an intersection of the secondsection 122 and the third section 124 of revolution 108A. Morespecifically, in order to prevent excessive hang ups during installationof the assembly 100, which may cause installer fatigue and/or damage tostuds of a structure being wired, it is advantageous to make VW as smallas possible relative to the other portions of the metal sheath 105. Forexample, a length ‘L’ (FIG. 4A) of the second section 122, along thelengthwise axis, may be at least three times as large/long as VW, and atleast two times as large as a diameter ‘D’ of the first section 120. Inthe embodiment shown, the diameter may be measured from a midpoint ofthe first end 121 of the first section 120, between the first surface127 and the second surface 129, and a midpoint of the second end 123 ofthe first section 120, between the first surface 127 and the secondsurface 129. In other embodiments, diameter may refer to an outerdiameter or an inner diameter of the first section 120.

In some embodiments, the length of the second section 122 may be betweentwo times and four times as large/long as VW. In some embodiments, thelength of the second section 122 may be between 1.5 times and ten timesas large/long as VW. In some embodiments, the length of the secondsection 122 may be between two times and five times as large/long as thediameter of the first section 120. In some embodiments, the length ofthe second section 122 may be between 1.5 times and ten times as largeas the diameter of the first section 120. Embodiments herein are notlimited in this context.

Furthermore, VW may be less than the diameter of the first section 120.More specifically, the diameter of the first section 120 may be between1.1 times and three times as large/long as VW. In other embodiments, thediameter of the first section 120 may be between 1.1 times and ten timesas large/long as VW. To further minimize VW, the free end 125 of thethird section 124 may extend past the plane 132 to provide a morecompact construction with a smaller valley depth ‘VD’ measured at apoint where an end surface 143 of the third section 124 of revolution108A engages the first surface 127 of the first section 120 ofrevolution 108B. For example, when the free end 125 of the third section124 extends at an angle between 5-15° relative to the plane 132, thefree end 125 of the third section 124 of revolution 108A may be closerto the second end 123 of the first section 120 of revolution 108B thanto the first end 121 of the first section 120 of revolution 108B. As theangle of the free end 125 of the third section 124 increases relative tothe plane 132, the valley depth decreases, which minimizes bothersomechatter and decreases a force required to pull the metal sheath 105through structures (e.g., studs) during installation of the assembly100. Instead, the revolutions 108A-108N will glide more easily across orthrough the structures.

FIG. 6 demonstrates a non-limiting example revolution 208 in greaterdetail. Although only a single revolution is shown, it will beappreciated that revolution 208 may be one of a plurality of revolutionshelically wound about one or more conductors to form a metal sheath,which may be substantially the same or similar to the metal sheath 105of the assembly 100 described herein. As shown, the revolution 208 mayinclude a first section 220 connected to a second section 222, and athird section 224 connected to the second section 222. The first section220 may include a first end 221 and a second end 223, and a firstsurface 227 opposite a second surface 229. The first section 220 mayhave a constant radius between the first end 221 and the second end 223.Although non-limiting, a first radius along the first surface 227 may be0.030 and a second radius along the second surface 229 may be 0.046″. Inother embodiments, the first and/or second radius may vary between thefirst end 221 and the second end 223. It will be appreciated that thefirst radius and the second radius may vary in other embodiments. Forexample, the first radius may be between 0.01 and 0.1 inches, and thesecond radius may be between 0.02 and 0.2 inches. The second radius mayvary based on a thickness of the first section 220.

The second section 222 may include a first end 237 and a second end 239,and a first surface 233 opposite second surface 235. The third section224 may include a first end 237 and a second end 239, wherein the secondend 239 may correspond to a free end 225 of the third section 224. Thesecond end 223 of the first section 220 may connect to the first end 237of the second section 222 at a first inflection point 238, while thesecond end 239 of the second section 222 may connect to the first end237 of the third section 224 at a second inflection point 240. In theembodiment shown, the first, second, and third sections 220, 222, 224have a constant thickness. Although non-limiting, the thickness may be0.016″, a helix pitch may be 0.270″, a strip length may be 0.375″, and alength of the second section 222 may be 0.188″. Therefore, the length ofthe second section 222 may be at least two times as large as thediameter of the first section 220 in the non-limiting embodiment shown.It will be appreciated that the thickness of the metal sheath 205 andthe length of the second section 222 may vary in other embodiments. Forexample, the thickness may be between 0.005 and 0.6 inches, while thelength of the second section 222 may be between 0.05 and 0.7 inches.

As shown, the revolution 208 may include a first axis 250 correspondingto a plane defined by the first surface 233 of the second section 222,and a second axis 252 defined by a plane that touches or intersects thefirst surface 227 of the first section 220 at an apex 256 (in theorientation shown). The first axis 250 may be parallel to the secondaxis 252. The second section 222 may extend generally parallel to thefirst axis 250 and to the second axis 252. The free end 225 of the thirdsection 224 may extend generally perpendicular to the first axis 250 andto the second axis 252. In the non-limiting embodiment shown, the firstend 221 of the first section 220 does not extend to or past the firstaxis 250, and the second section 239 of the third section 224 does notextend to or past the second axis 252. For example, an end surface 260of the free end 225 may be approximately 0.002″ away from the secondaxis 252 to permit movement of the revolution 208. Furthermore, a planedefined by an end surface 258 of the first section 220 may be orientedat a non-zero angle relative to the first axis 250 to increase movement,while a plane defined by the end surface 260 of the free end 225 may beoriented substantially parallel to the second axis 252.

FIGS. 7A-7B demonstrate a non-limiting example revolution 308 of a metalsheath 305 in greater detail. As shown, the revolution 308 may include afirst section 320 connected to a second section 322, and a third section324 connected to the second section 322. As best shown in FIG. 7A, thefirst section 320 may include a first end 321 and a second end 323, anda first surface 327 opposite a second surface 329. The first section 320may have a constant radius between the first end 321 and the second end323. Although non-limiting, a first radius along the first surface 327may be 0.030″ and a second radius along the second surface 329 may be0.042″. In other embodiments, the first and/or second radius may varybetween the first end 321 and the second end 323. It will be appreciatedthat the first radius and the second radius may vary in otherembodiments. For example, the first radius may be between 0.01 and 0.1inches, and the second radius may be between 0.02 and 0.2 inches. Thesecond radius may vary based on a thickness of the first section 320.

The second section 322 may include a first end 337 and a second end 339,and a first surface 333 opposite a second surface 335. The third section324 may include a first end 337 and a second end 339, wherein the secondend 339 may correspond to a free end 325 of the third section 324. Thesecond end 323 of the first section 320 may connect to the first end 337of the second section 322 at a first inflection point 338, while thesecond end 339 of the second section 322 may connect to the first end337 of the third section 324 at a second inflection point 340. In theembodiment shown, the first, second, and third sections 320, 322, 324may have a constant thickness. Although non-limiting, the thickness maybe 0.012″, a helix pitch may be 0.272″, a strip length may be 0.375″,and a length of the second section 322 may be 0.188″. The helix pitch isa distance between the apex 356 of the first section 320 and a midpointof an end surface 360 of the free end 325. In some embodiments, thelength of the second section 322 is at least two times as large as thediameter of the first section 320. It will be appreciated that thethickness of the metal sheath 205 and the length of the second section322 may vary in other embodiments. For example, the thickness may bebetween 0.005 and 0.6 inches, while the length of the second section 322may be between 0.05 and 0.7 inches.

As further shown, the revolution 308 may include a first axis 350corresponding to a plane defined by the first surface 333 of the secondsection 322, and a second axis 352 defined by a plane that touches orintersects the first surface 327 of the first section 320 at the apex356 (in the orientation shown). The first axis 350 may be parallel tothe second axis 352. The second section 322 may extend generallyparallel to the first axis 350 and to the second axis 352. The free end325 of the third section 324 may extend generally perpendicular to thefirst axis 350 and to the second axis 352. In the non-limitingembodiment shown, the first end 321 of the first section 320 does notextend to or past the first axis 350, and the second end 339 of thethird section 324 does not extend to or past the second axis 352. Forexample, an end surface 358 of the first section 320 may beapproximately 0.006″ away from the first axis 350. Furthermore, a planedefined by the end surface 358 of the first section 320 may besubstantially parallel to the first axis 350, while a plane defined bythe end surface 360 of the free end 325 may be oriented substantiallyparallel to the second axis 352.

As best shown in FIG. 7B, a valley width (VW) between the secondinflection point 340 of revolution 308 and the first inflection point338 of revolution 308-1 may be 0.084″. Therefore, the length of thesecond section 322 may be at least two times as large as VW when themetal sheath 305 is in a linear configuration. Furthermore, the helixpitch may be at least three times as large as VW when the metal sheath305 is in the linear configuration. It will be appreciated that VW mayvary in other embodiments. For example, VW may be between 0.03 and 0.3inches.

FIGS. 8A-8B demonstrate a non-limiting example revolution 408 of a metalsheath 405 in greater detail. As shown, the revolution 408 may include afirst section 420 connected to a second section 422, and a third section424 connected to the second section 422. As best shown in FIG. 8A, thefirst section 420 may include a first end 421 and a second end 423, anda first surface 427 opposite a second surface 429. The first section 420may have a constant radius between the first end 421 and the second end423. Although non-limiting, a first radius along the first surface 427may be 0.040″, while a second radius along the second surface 429 may be0.074″. In other embodiments, the first and/or second radius may varybetween the first end 421 and the second end 423. It will be appreciatedthat the first radius and the second radius may vary in otherembodiments. For example, the first radius may be between 0.01 and 0.1inches, and the second radius may be between 0.02 and 0.2 inches. Thesecond radius may vary based on a thickness of the first section 420.

The second section 422 may include a first end 437 and a second end 439,and a first surface 433 opposite a second surface 435. The third section424 may include a first end 437 and a second end 439, wherein the secondend 439 may correspond to a free end 425 of the third section 424. Thesecond end 423 of the first section 420 may connect to the first end 437of the second section 422 at a first inflection point 438, while thesecond end 439 of the second section 422 may connect to the first end437 of the third section 424 at a second inflection point 440. In theembodiment shown, the first, second, and third sections 420, 422, 424may have a constant thickness. Although non-limiting, the thickness maybe 0.034″, a helix pitch may be 0.372″, a strip length may be 0.50″, anda length of the second section 422 may be 0.265″. The helix pitch is adistance between the apex 456 of the first section 420 and a midpoint ofan end surface 460 of the free end 425. In some embodiments, the lengthof the second section 422 is at least two times as large as the diameterof the first section 420. It will be appreciated that the thickness ofthe metal sheath 405 and the length of the second section 422 may varyin other embodiments. For example, the thickness may be between 0.005and 0.6 inches, while the length of the second section 422 may bebetween 0.05 and 0.7 inches.

As further shown, the revolution 408 may include a first axis 450corresponding to a plane defined by the first surface 433 of the secondsection 422, and a second axis 452 defined by a plane that touches orintersects the first surface 427 of the first section 420 at the apex456 (in the orientation shown). The first axis 450 may be parallel tothe second axis 452. The second section 422 may extend generallyparallel to the first axis 450 and to the second axis 452. The free end425 of the third section 424 may extend generally perpendicular to thefirst axis 450 and to the second axis 452. In the non-limitingembodiment shown, the first end 421 of the first section 420 may extendnearly to the first axis 450, and the second end 439 of the thirdsection 424 may nearly extend to the second axis 452. For example, anend surface 458 of the first section 420 and an end surface 460 of thethird section 424 may be approximately 0.002″ away from the first axis450 and second axis 452, respectively. Furthermore, a plane defined bythe end surface 458 of the first section 420 may be oriented at a firstnon-zero angle relative to the first axis 450, while a plane defined bythe end surface 460 of the free end 425 may be oriented at a secondnon-zero angle relative to the second axis 452. In various embodiments,the first and second non-zero angles may be the same or different.

As best shown in FIG. 8B, a valley width (VW) between the secondinflection point 440 of revolution 408 and the first inflection point438 of revolution 408-1 may be 0.107″. Therefore, the length of thesecond section 422 may be approximately 2.5 times as large as VW whenthe metal sheath 405 is in a linear configuration. Furthermore, thehelix pitch may be approximately 3.5 times as large as VW when the metalsheath 405 is in the linear configuration. It will be appreciated thatVW may vary in other embodiments. For example, VW may be between 0.03and 0.3 inches.

FIG. 9 demonstrates a non-limiting example metal sheath 505 in greaterdetail. As shown, each revolution 508 and 508-1 may include a firstsection 520 connected to a second section 522, and a third section 524connected to the second section 522. In various embodiments, the firstsection 520 may have a constant or varied radius along its length.Although non-limiting, a first radius along a first surface (outerfacing) of the first section 520 may be 0.030″, while a second radiusalong a second surface (inner facing) may be 0.050″. It will beappreciated that the first radius and the second radius may vary inother embodiments. For example, the first radius may be between 0.01 and0.1 inches, and the second radius may be between 0.02 and 0.2 inches.The second radius may vary based on a thickness of the first section520.

Furthermore, a helix pitch may be 0.39″ and a length of the secondsection 522 may be 0.3131″. It will be appreciated that the length ofthe second section 522 may vary in other embodiments. For example, thelength of the second section 522 may be between 0.05 and 0.7 inches. Insome embodiments, the length of the second section 522 may be betweentwo and five times as large as the diameter of the first section 520.

A valley width (VW) between a second inflection point 540 of revolution508 and a first inflection point 538 of revolution 508-1 may be 0.0769″.Therefore, the length of the second section 522 may be between two andfour times as large as Vw when the metal sheath 505 is in a linearconfiguration. Furthermore, the helix pitch may be between two and fivetimes as large as VW when the metal sheath 505 is in the linearconfiguration. It will be appreciated that VW may vary in otherembodiments. For example, VW may be between 0.03 and 0.3 inches.

FIG. 10 demonstrates a coil of an MC cable assembly (hereinafter“assembly”) 600 according to embodiments of the disclosure. The assembly600 may the same or similar to any of the MC cable assemblies describedherein. Assembly 600 may include a metal sheath 605 formed from a flator shaped metal strip, the edges of which are helically wrapped andinterlock to form a series of revolutions 608. Each of the revolutions608 includes a series of peaks 614 and valleys 616. The profile of themetal sheath 605 allows the resulting assembly 600 to have a desiredbend radius for compact and efficient packaging. For example, whenarranged as a series of loops in a coil configuration, e.g., as shown,the metal sheath 605 may have a minimum bend radius between three andfifteen times an overall diameter of the metal sheath 605.

Furthermore, due to the exterior profile of the metal sheath 605, suchas a length of the peaks 614 being at least three times as large as thevalleys 616, nesting of the peaks 614 and the valleys 616 of adjacentloops of the metal sheath 605 when stacked upon one another can beminimized, thus making it easier for the assembly 600 to be unwound foruse. This may be similarly true when the assembly 600 is dispensed froma reel 660, as demonstrated in FIG. 11. As known, the reel 660 mayinclude a central body about which the metal sheath 605 is wound, andone or more flanges 662A and 662B on opposite sides of the central body.As the metal sheath 605 is pulled, the reel 660 rotates to dispense themetal sheath 605 therefrom. The profile of the metal sheath 605 allowsthe various loops of the metal sheath 605 to slide over/atop one anotheras the metal sheath 605 is being pulled. Because the valleys 616 andpeaks 614 are less likely to nest or get caught with one another, theassembly 600 can more quickly and consistently be unwound for use duringinstallation.

Another advantage of the MC cable assemblies described herein isdemonstrated in FIGS. 12A-12B. Oftentimes MC cable is suitable for usein commercial and industrial settings having a plurality of supportstructures 765, such as metal framing studs, including one or more cableopenings 766 formed therein. Although not a requirement, MC cable may beinstalled after the rough-in phase of locating and setting all boxes andenclosures, wherein rough-in occurs when all the interior and exteriorwalls are framed but before the sheet rock or other finishing materialis installed. As better shown in FIG. 12B, the cable openings 766 mayinclude a larger upper section 777 and a relatively smaller bottomsection 778. It will be appreciated that other differently sized/shapedcable openings 766 are possible. During installation, an installer maypass an MC cable assembly 700 through the cable openings 766, asdesired. As a result, the peaks 714 and the valleys 716 of the metalsheath 705 may drag or brush against an interior edge 770 of the cableopenings 766. The MC cable assembly 700 may be the same or similar tothe MC cable assemblies described herein.

In general, as the length of the MC cable assembly 700 increases so doesthe required pulling force. In contrast to prior art MC cableassemblies, which include larger valleys between revolutions and morepronounced peaks, the outer profile of the MC cable assembly 700 mayinclude a flattened peak (e.g., second section) 714 along the outermostradial portion of the metal sheath 705 and relatively narrow valleys 716between the peaks 714 to decrease engagement between the outer surfaceof the metal sheath 705 and the interior edge 770 of the cable openings766. Furthermore, due to the proportions of the length of the flattenedpeak 714 to the diameter of the first section and to a width of thevalleys 716, excessive hang-ups and audible noise (“chatter”) arereduced during installation of the metal sheath, leading to decreasedinstaller fatigue and increased installation efficiency. The exteriorprofile of the metal sheath 705 allows the MC cable assembly 700 to moreeasily glide through the support structures 765.

Furthermore, in some cases it may be desirable to bend or fold the MCcable assembly 700, for example, to wrap around a corner or stud. Themetal sheath 705 of the MC cable assembly 700 has increasedconfigurability due to the tighter bend radius. As recited above, the MCcable assembly 700 may have a minimum bend radius between three andfifteen times an overall diameter of the metal sheath 705 while stillmeeting performance crush requirements for MC cables. For example, MCcables assemblies of the present disclosure may withstand greater than1000 lbf. In the case the MC cable assembly 700 has a diameter of 0.5″,the bend radius may be as tight as 1.5″. Embodiments herein are notlimited in this context.

FIG. 13 is a flowchart of a method 800 for forming a MC cable accordingto embodiments of the present disclosure. At a block 801, the method 800may include cabling a plurality of conductors together. In variousembodiments, the conductors may be twisted or laid parallel to oneanother. In other embodiments, a single conductor is provided.

At block 802, the method 800 may include passing a single continuousstrip of metal through a die or other similar machine to form the stripof metal with a desired profile. In some embodiments, the metal sheathmay be formed to include a first section connected to a second section,and a third section connected to the second section. In someembodiments, more than one strip of metal may be used.

At block 803, the method 800 may include wrapping the strip of metalaround the plurality of conductors to create a metal sheath, the metalsheath comprising a series of helical revolutions extending along alengthwise axis. In some embodiments, at least two helical revolutionsof the series of helical revolutions each include a first section havinga curved profile, wherein the curved profile extends into an interiorcavity of the metal sheath, and a second section extending from thefirst section, the second section extending along the lengthwise axis.In some embodiments, the second section may extend parallel to thelengthwise axis. The at least two helical revolutions of the series ofhelical revolutions may each further include a third section extendingfrom the second section, the third section including a free endterminating within a recess defined by a first section of an adjacenthelical revolution of the series of helical revolutions, wherein thefirst section and the second section connect at a first inflectionpoint, wherein the second section and the third section connect at asecond inflection point, and wherein a length of the second section isat least two times as large as a distance between the second inflectionpoint and the first inflection point of the adjacent helical revolutionof the series of helical revolutions when the metal sheath is in alinear configuration. In some embodiments, the length of the secondsection is at least three times as large as the distance between thesecond inflection point and the first inflection point of the adjacenthelical revolution of the series of helical revolutions.

In some embodiments, the helically wrapping may include arranging theseries of helical revolutions such that the free end of the thirdsection extends past a plane defined by a bottom most point of the firstsection of the adjacent helical revolution. In some embodiments, thehelically wrapping further includes arranging the series of helicalrevolutions such that the free end of the third section is in abutmentwith an inner surface of the first section of the adjacent helicalrevolution. In some embodiments, the helically wrapping further includesarranging the series of helical revolutions such that the second sectionis oriented co-planar with a second section of the adjacent helicalrevolution when the metal sheath is in the linear configuration.

Although the illustrative method 800 is described as a series of acts orevents, the present disclosure is not limited by the illustratedordering of such acts or events unless specifically stated. For example,some acts may occur in different orders and/or concurrently with otheracts or events apart from those illustrated and/or described herein, inaccordance with the disclosure. In addition, not all illustrated acts orevents may be necessary to implement a methodology in accordance withthe present disclosure.

Although non-limiting, cables of the present disclosure may beappropriate for commercial, industrial, multi-residential branchcircuits and feeder wiring, services for power, lighting, control andsignal circuits. Furthermore, cables of the present disclosure may beexposed or concealed, fished, surface mounted, embedded in plaster, usedin environmental air-handling spaces, used in open or messengersupported aerial runs, used in dry locations, used in hazardouslocations to Class I & II Div. 2 and Class III, Div. 1 & 2 (per NEC®Articles 501, 502, 503, 530, etc.

The foregoing discussion has been presented for purposes of illustrationand description and is not intended to limit the disclosure to the formor forms disclosed herein. For example, various features of thedisclosure may be grouped together in one or more aspects, embodiments,or configurations for the purpose of streamlining the disclosure.However, it should be understood that various features of the certainaspects, embodiments, or configurations of the disclosure may becombined in alternate aspects, embodiments, or configurations. Moreover,the following claims are hereby incorporated into this DetailedDescription by this reference, with each claim standing on its own as aseparate embodiment of the present disclosure.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralelements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present disclosureare not intended to be interpreted as excluding the existence ofadditional embodiments that also incorporate the recited features.

The use of “including,” “comprising,” or “having” and variations thereofherein is meant to encompass the items listed thereafter and equivalentsthereof as well as additional items. Accordingly, the terms “including,”“comprising,” or “having” and variations thereof are open-endedexpressions and can be used interchangeably herein.

The phrases “at least one”, “one or more”, and “and/or”, as used herein,are open-ended expressions that are both conjunctive and disjunctive inoperation. For example, each of the expressions “at least one of A, Band C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “oneor more of A, B, or C” and “A, B, and/or C” means A alone, B alone, Calone, A and B together, A and C together, B and C together, or A, B andC together.

All directional references (e.g., proximal, distal, upper, lower,upward, downward, left, right, lateral, longitudinal, front, back, top,bottom, above, below, vertical, horizontal, radial, axial, clockwise,and counterclockwise) are only used for identification purposes to aidthe reader's understanding of the present disclosure, and do not createlimitations, particularly as to the position, orientation, or use ofthis disclosure. Connection references (e.g., attached, coupled,connected, and joined) are to be construed broadly and may includeintermediate members between a collection of elements and relativemovement between elements unless otherwise indicated. As such,connection references do not necessarily infer that two elements aredirectly connected and in fixed relation to each other.

Furthermore, identification references (e.g., primary, secondary, first,second, third, fourth, etc.) are not intended to connote importance orpriority, but are used to distinguish one feature from another. Thedrawings are for purposes of illustration only and the dimensions,positions, order and relative sizes reflected in the drawings attachedhereto may vary.

The terms “substantial” or “substantially,” as well as the terms“approximate” or “approximately,” can be used interchangeably in someembodiments, and can be described using any relative measures acceptableby one of ordinary skill in the art. For example, these terms can serveas a comparison to a reference parameter, to indicate a deviationcapable of providing the intended function. Although non-limiting, thedeviation from the reference parameter can be, for example, in an amountof less than 1%, less than 3%, less than 5%, less than 10%, less than15%, less than 20%, and so on.

The present disclosure is not to be limited in scope by the specificembodiments described herein. Indeed, other various embodiments of andmodifications to the present disclosure, in addition to those describedherein, will be apparent to those of ordinary skill in the art from theforegoing description and accompanying drawings. Thus, such otherembodiments and modifications are intended to fall within the scope ofthe present disclosure. Furthermore, the present disclosure has beendescribed herein in the context of a particular implementation in aparticular environment for a particular purpose. Those of ordinary skillin the art will recognize the usefulness is not limited thereto and thepresent disclosure may be beneficially implemented in any number ofenvironments for any number of purposes. Thus, the claims set forthbelow are to be construed in view of the full breadth and spirit of thepresent disclosure as described herein.

What is claimed is:
 1. A cable assembly, comprising: at least one conductor; and a metal sheath disposed over the at least one conductor, the metal sheath comprising a continuous strip of metal having a plurality of revolutions, at least a first revolution of the plurality of revolutions including: a first section having a curved profile extending into an interior cavity of the metal sheath; a second section extending from the first section, the second section extending along a lengthwise axis, wherein a length of the second section, along the lengthwise axis, is at least two times as large as a diameter of the first section when the metal sheath is in a linear configuration; and a third section extending from the second section, the third section including a free end terminating within a recess defined by a curved profile of a first section of an adjacent revolution of the plurality of revolutions.
 2. The cable assembly of claim 1, wherein the first section and the second section of the first revolution connect at a first inflection point, wherein the second section and the third section of the first revolution connect at a second inflection point, and wherein the adjacent revolution has a second section extending from the first section, the second section extending along the lengthwise axis, and wherein the first section and second section of the adjacent revolution connect at a first inflection point of the adjacent revolution, and wherein a distance between the second inflection point of the first revolution and the first inflection point of the adjacent revolution, along the lengthwise axis, is less than the diameter of the first section of the first revolution when the metal sheath is in a linear configuration.
 3. The cable assembly of claim 2, wherein the length of the second section of the first revolution is also at least three times as large as the distance between the second inflection point of the first revolution and the first inflection point of the adjacent revolution when the metal sheath is in a linear configuration.
 4. The cable assembly of claim 1, wherein the second section of the first revolution and the second section of the adjacent revolution are oriented along different planes when the metal sheath is in a linear configuration.
 5. The cable assembly of claim 1, the free end of the third section of the first revolution extending past a plane defined by a bottom most point of the first section of the adjacent revolution, the plane extending perpendicular to the second section.
 6. The cable assembly of claim 5, wherein the free end of the third section extends towards an interior cavity of the metal sheath at a non-zero angle with respect to the plane.
 7. A metal-clad (MC) cable assembly, comprising: a plurality of conductors cabled together; and a metal sheath comprising a single metal strip wound around the plurality of conductors in a series of helical revolutions extending along a lengthwise axis, a first helical revolution of the series of helical revolutions including: a first section having a profile extending into an interior cavity of the metal sheath; a second section extending from the first section, wherein the second section extends into the interior cavity defined by the series of helical revolutions; and a third section extending from the second section, the third section including a free end terminating within a recess defined by a first section of an adjacent helical revolution of the series of helical revolutions, wherein the first section and the second section of the first helical revolution connect at a first inflection point, wherein the second section and the third section of the first helical revolution connect at a second inflection point, and wherein a length of the second section of the first helical revolution is at least three times as large as a distance between the second inflection point of the first helical revolution and a first inflection point of the adjacent helical revolution of the series of helical revolutions when the metal sheath is in a linear configuration.
 8. The MC cable assembly of claim 7, wherein the free end of the third section is in abutment with an inner surface of the first section of the adjacent helical revolution.
 9. The MC cable assembly of claim 8, wherein the third section of the first helical revolution mechanically interlocks with the first section of the adjacent revolution.
 10. A metal-clad (MC) cable assembly, comprising: a plurality of conductors extending along a lengthwise axis; and a metal sheath wound helically around the plurality of conductors in a series of convolutions, the series of convolutions comprising a first convolution in direct abutment with a second convolution, wherein the first convolution comprises: a first convolution first section having a first curved profile, wherein the first curved profile extends into an interior cavity of the metal sheath; a first convolution second section extending from the first convolution first section at a first convolution first inflection point, the first convolution second section extending along to the lengthwise axis; and a first convolution third section extending from the first convolution second section at a first convolution second inflection point, wherein the second convolution comprises: a second convolution first section having a second curved profile, wherein the second curved profile extends into the interior cavity of the metal sheath; a second convolution second section extending from the second convolution first section at a second convolution first inflection point, the second convolution second section extending along the lengthwise axis; and a second convolution third section extending from the second convolution second section at a second convolution second inflection point, wherein the first convolution third section terminates within a recess defined the second convolution first section, wherein a length of the first convolution second section, along the lengthwise axis, is at least two times as large as a diameter of the first convolution first section when the metal sheath is in a linear configuration.
 11. The MC cable assembly of claim 10, wherein the length of the first convolution second section is also at least three times as large as a distance between the first convolution second inflection point and the second convolution first inflection point when the metal sheath is in a linear configuration, and wherein the diameter of the first convolution first section is greater than the distance between the first convolution second inflection point and the second convolution first inflection point.
 12. The MC cable assembly of claim 10, wherein the first convolution third section mechanically interlocks with the second convolution first section.
 13. The MC cable assembly of claim 10, wherein the first convolution second section and the second convolution second section each have a planar profile extending along the lengthwise axis.
 14. The MC cable assembly of claim 10, wherein the metal sheath has a thickness between 0.005 and 0.060 inches.
 15. The MC cable assembly of claim 10, wherein the metal sheath has a bend radius between three and fifteen times a radius of the metal sheath.
 16. A method of forming a metal-clad (MC) cable assembly, comprising: cabling a plurality of conductors together; and helically wrapping a strip of metal around a plurality of conductors to create a metal sheath, the metal sheath comprising a series of helical revolutions extending along a lengthwise axis, at least two helical revolutions of the series of helical revolutions each including: a first section having a curved profile, wherein the curved profile is concave relative to the lengthwise axis; a second section extending from the first section, the second section extending parallel to the lengthwise axis; and a third section extending from the second section, the third section including a free end terminating within a recess defined by a first section of an adjacent helical revolution of the series of helical revolutions, wherein the first section and the second section connect at a first inflection point, wherein the second section and the third section connect at a second inflection point, and wherein a length of the second section is at least three times as large as a distance between the second inflection point and the first inflection point of the adjacent helical revolution of the series of helical revolutions when the metal sheath is in a linear configuration.
 17. The method of claim 16, wherein the helically wrapping comprises arranging the series of helical revolutions such that the free end of the third section extends past a plane defined by a bottom most point of the first section of the adjacent helical revolution.
 18. The method of claim 17, wherein the helically wrapping further comprises arranging the series of helical revolutions such that the free end of the third section is in abutment with an inner surface of the first section of the adjacent helical revolution.
 19. The method of claim 16, wherein the helically wrapping comprises arranging the series of helical revolutions such that the second section is oriented co-planar with a second section of the adjacent helical revolution when the metal sheath is in the linear configuration.
 20. The method of claim 16, further comprising passing the strip of metal through a die to: form the curved profile of the first section, form a second profile of the second section, and form a third profile of the third section. 